To provide a smooth ride in rough water, various hull constructions use a downwardly pointing V-bottom, at least at the keel line, which increases in inclination near the bow. The deep-V hull and the cathedral hull are of this type. Also catamarans, trimarans and other multihull craft often consist of two or more such hulls joined together.
However, when moving with the waves, these hulls fall off one wave and plow into the next where their sharply inclined bow surfaces act like a rudder around which they rotate or broach. Yet their wide amidship bottom surfaces still pound against oncoming waves.
Further, at high planing speeds, these hulls need to have their center of gravity substantially rearward of amidship in order to keep the bow up and reduce wetted area which reduces frictional drag, but such a rearward center of gravity causes excess bow rise at low speed.
Further if the angle of the V is not deep, these hulls tend to skid excessively in a turn.
Examples of various types of hulls designed to improve rough water performance and handling are disclosed in U.S. Pat. Nos. 1,729,446, 2,980,924, 3,117,544, 3,160,134, 3,203,389, 3,363,598, 3,547,064 and 3,763,810.